Calibration and monitoring of a kitchen hood system

ABSTRACT

Systems and methods calibrate and monitor optic sensors associated with a kitchen hood system. Embodiments of the present invention relate to adequately exhausting a gaseous substance while minimizing the devotion of unnecessary energy. A controller calibrates a magnitude of a signal emitted and received between optic sensors by adjusting a gain associated with the signal until the magnitude of the signal is within an optimal threshold. The controller also monitors the magnitude of the calibrated signal for fluctuations in the magnitude of the calibrated signal beyond at least one specified threshold. The controller also initiates at least one graduated action when the magnitude of the calibrated signal fluctuates beyond the at least one specified threshold. The graduated action reduces an overall amount of energy consumed by the at least one kitchen hood system and/or recalibrates the magnitude of the signal.

The present application claims the benefit of U.S. Provisional Application Ser. No. 62/102,340, filed Jan. 12, 2015, the disclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to kitchen hood systems and specifically to improving the energy efficiency of kitchen hood systems.

BACKGROUND OF THE INVENTION

Commercial and institutional kitchens are equipped to prepare food for large numbers of people and may form part of or adjoin larger facilities such as restaurants, hospitals and the like. Such kitchens are typically equipped with one or more commercial duty cooking units capable of cooking large amounts of food. On such a scale, the cooking process may generate substantial amounts of cooking heat and airborne cooking by-products such as water vapor, grease particulates, smoke and aerosols, all of which must be exhausted from the kitchen so as not to foul the environment of the facility. To this end, large exhaust hoods are usually provided over the cooking units, with duct work connecting the hood to a motor driven exhaust fan located outside the facility such as on the roof or on the outside of an external wall. As the fan is rotated by the motor, air within the kitchen environment is drawn into the hood and exhausted to the outside atmosphere. In this way, cooking heat and cooking by-products generated by the cooking units follow an air flow path defined between the cooking units and outside through the hood to be exhausted from the kitchen before they escape into the main kitchen environment and perhaps into the rest of the facility.

In many conventional installations, the motor driving the exhaust fan rotates at a fixed speed. The exhaust fan thus rotates at a fixed speed as well and, therefore, tends to draw air through the hood at a constant or fixed volume rate without regard to the amount of heat or cooking by-product actually being generated. As a result, there are often times throughout a working shift where the system may be under or over-exhausting. Under-exhausting allows heat and/or cooking by-products to build up in the kitchen or other parts of the facility, which can create discomfort and also overload the building heating and ventilation or air conditioning systems (“HVAC”). Similarly, over-exhausting wastes air that has been conditioned by the building HVAC, thus requiring further burden on the HVAC systems to make up the loss. Over-exhausting also results in energy inefficiencies with regards to the system in which the fixed speed that the exhaust fan is operating exceeds what is necessary to adequately remove heat or cooking by-product from the kitchen. Thus, unnecessary energy is devoted to the system during over-exhausting which translates to an unnecessary increase in cost associated with removing heat or cooking by-product from the kitchen.

SUMMARY OF THE INVENTION

The present invention overcomes the foregoing problems and other known shortcomings, drawbacks, and challenges of calibrating optic sensors associated with a kitchen hood system and then monitoring the optic sensors so that appropriate action may be taken with regards to the kitchen hood system to optimize the amount of energy used by the kitchen hood system. While the present invention will be described in connection with certain embodiments, it will be understood that the present invention is not limited to these embodiments. To the contrary, the present invention includes all alternatives, modifications, and equivalents as may be included within the spirit and scope of the present invention.

In one embodiment of the present invention, a computer implemented method calibrates and monitors at least one optic sensor associated with at least one kitchen hood system. A signal is emitted by a first optic sensor and received by a second optic sensor that is in alignment with the first optic sensor. The magnitude of the signal is calibrated by a controller by adjusting a gain associated with the signal until the magnitude of the signal is within an optimal threshold. The magnitude of the calibrated signal is monitored by the controller for fluctuations in the magnitude of the calibrated signal beyond at least one specified threshold. At least one graduated action is initiated by the controller when the magnitude of the calibrated signal fluctuates beyond the at least one specified threshold. The graduation action reduces an overall amount of energy consumed by the at least one kitchen hood system and/or recalibrates the magnitude of the signal.

In another embodiment of the present invention, a system calibrates and monitors at least one optic sensor associated with at least one kitchen hood system. A first optic sensor is configured to emit a signal. A second optic sensor is aligned with the first optic sensor and is configured to receive the signal emitted by the first optic sensor. A controller is configured to calibrate a magnitude of the signal by adjusting a gain associated with the signal until the magnitude of the signal is within an optimal threshold. The controller is also configured to monitor the magnitude of the calibrated signal for fluctuations in the magnitude of the calibrated signal beyond at least one specified threshold. The controller is also configured to initiate at least one graduated action when the magnitude of the calibrated signal fluctuates beyond the at least one specified threshold. The graduated action reduces an overall amount of energy consumed by the at least one kitchen hood system and/or recalibrates the magnitude of the signal.

Further embodiments, features, and advantages, as well as the structure and operation of the various embodiments, are described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are described with reference to the accompanying drawings. In the drawings, like reference numbers may indicate identical or functionally similar elements.

FIG. 1 is a perspective view diagrammatically illustrating a restaurant or institutional facility, primarily the kitchen area and cooking units, including a kitchen exhaust system in which embodiments of the present invention, or portions thereof, may be implemented;

FIG. 2 is a cross-sectional view of the gaseous substance sensor of FIG. 1 in which embodiments of the present invention, or portions thereof, can be implemented;

FIG. 3 is a block diagram of an exhaust system for use in the kitchen exhaust system of FIG. 1 in which embodiments of the present invention, or portions thereof, can be implemented;

FIG. 4 is a flowchart showing an example method for automatic calibration of the gaseous substance sensor that may be executed by the control module and the gaseous substance sensor;

FIG. 5 illustrates an automatic calibration system in which embodiments of the present invention, or portions thereof, may be implemented;

FIG. 6 is a flowchart showing an example method for transitioning the fan between an inactive mode and an active mode that may be initiated by the control module and the motor speed controller;

FIG. 7 is a flowchart showing an example method for modulating the velocity of the fan based on the density of the gaseous substance within the exhaust hood;

FIG. 8 is a flowchart showing an example method for detecting a blockage located in the exhaust hood and initiating the appropriate graduated actions so that unnecessary energy in operating the fan is not devoted to attempting to remove the blockage;

FIG. 9 is a flowchart showing an example method for determining whether auxiliary accessories associated with the exhaust of the gaseous substance from the exhaust hood may be deactivated when activation of the auxiliary accessories is not necessary;

FIG. 10 is a flowchart showing an example method for determining when recalibration of the signal should occur.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally relates to the field of commercial and institutional kitchen exhaust systems. In an exemplary embodiment of the present invention, a controller calibrates a magnitude of a signal generated between optic sensors and then monitors the calibrated signal so that different graduated actions may be initiated by the controller in response to the behavior of the calibrated signal. The controller may initially calibrate the magnitude of the signal between the optic sensors to account for any fouling that may have accumulated on the optic sensors. In doing so, the controller may adjust a gain associated with the signal until the gain is within an optimal threshold. The magnitude of the calibrated signal resulting from the selected gain may then be used by the controller as a baseline in monitoring the calibrated signal for any fluctuations in the magnitude of the calibrated signal so that the amount of cleaning required of the optic sensors may be reduced and/or eliminated altogether.

Different fluctuations in the magnitude of the calibrated signal may be indicative that the amount of energy consumed by the kitchen hood system may be reduced. As the controller continuously monitors the magnitude of the calibrated signal for fluctuations, the controller may initiate graduated actions based on the behavior in the magnitude of the calibrated signal. The graduated actions when initiated and timed with a specific behavior in the magnitude of the calibrated signal may result in a reduction in the overall amount of energy consumed by the kitchen hood system. The graduated action may also include a recalibration of the calibrated signal to ensure any fluctuation in the magnitude of the calibrated signal still exists.

In the Detailed Description herein, references to “one embodiment”, “an embodiment”, an “example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment of the present invention, Applicants submit that it may be within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments of the present invention whether or not explicitly described.

Embodiments of the present invention may be implemented in hardware, software, or any combination thereof. Embodiments of the invention may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Further, firmware, software, routines, instructions may be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions in fact result from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc.

For purposes of this discussion, each of the various components discussed can be considered a module, and the term “module” shall be understood to include at least one software, firmware, and hardware (such as one or more circuit, microchip, or device, or any combination thereof), and any combination thereof. In addition, it will be understood that each module can include one, or more than one, component within an actual device, and each component that forms a part of the described module can function either cooperatively or independently of any other component forming a part of the module. Conversely, multiple modules described herein can represent a single component within an actual device. Further components within a module can be in a single device or distributed among multiple devices in a wired or wireless manner.

The following detailed description refers to the accompanying drawings that illustrate exemplary embodiments of the present invention. Other embodiments are possible, and modifications can be made to the embodiments within the spirit and scope of this description. Those skilled in the art with access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which embodiments would be of significant utility. Therefore, the detailed description is not meant to limit the present invention to the embodiments described below.

Referring to FIG. 1, a facility 10 such as a restaurant or institutional facility includes a kitchen 12 and at least one adjacent room such as a dining room 14 with an interior wall 16 separating the two rooms 12, 14. The kitchen 12 includes a plurality of commercial cooking units 18 such as one or more stoves, ovens, griddles and the like. The facility 10 is surrounded by an enclosure 20 (defined by a roof 22 and exterior walls 24 only one of which is shown in FIG. 1) which separates the outside environment 26 from the inside ambient air environment 28 of the facility 10 including the kitchen 12. The facility 10 is also equipped with a heating, ventilating and air conditioning system (“HVAC”) as at 30 which maintains the inside environment 28 at a suitable condition for the use of the occupants of the facility 10.

Associated with kitchen 12 is kitchen hood system 32 including an exhaust hood 34 situated over the cooking units 18 and fluidly coupled with an exhaust assembly 36 through a duct 38. Hood 34 may be generally rectangular with a top wall 42 and depending front, sides and back walls 43, 44 and 45 to define an internal volume 46 which fluidly couples to a downwardly facing opening 48 to cooking units 18. The internal volume 46 is also fluidly coupled with exhaust assembly 36 via the duct 38 connected through top wall 42. A filter assembly (not shown) may be installed in exhaust hood 34 to filter air pulled into duct 38 by the exhaust assembly 36. The duct 38 extends upwardly through the roof 22 of enclosure 20 and terminates in exhaust assembly 36 by which to exhaust air from the internal volume 46 to the outside environment 26. Exhaust assembly 36 may include at least one fan motor and associated with at least one fan 50 by which to expel air from the exhaust assembly 36 at a volume rate. The quantity of fans 50 included in the exhaust assembly 36 may include any quantity of fans sufficient to exhaust gaseous substances from the exhaust hood 34 that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

Thus, when fan 50 is running, an air flow path 52 is defined between cooking units 18 and outside environment 26 through downwardly facing opening 48 of the hood 34, the internal volume 46, and duct 38. As air follows the air flow path 52, gaseous substances generated by the cooking units 18 are drawn along to be exhausted to the outside environment 26 rather than into the rest of the facility 10. Air exhausted along the air flow path 52 is replaced by air from the ambient air environment 28 (which is defined as being outside of exhaust hood 34 and spaced away from air flow path 52) such that air is also drawn from environment 28 through hood 34 as indicated by arrow 54.

In order for the fan 50 to adequately exhaust the gaseous substance from the exhaust hood 34, the fan 50 should operate at a velocity that correlates to the volume of gaseous substance located within the exhaust hood 34. For example, as the volume of gaseous substance located within the exhaust hood 34 increases, the velocity at which the fan 50 operates should also increase in order to adequately exhaust the gaseous substance from the exhaust hood 34. The gaseous substance may represent gases generated when the cooking units 18 are in operation in that the generated gases have a temperature that may be readily detected by an exhaust temperature sensor 76. The gaseous substance may also include by-products generated when the cooking units 18 are in operation but do not have a temperature associated with such by-products that may not be readily detected by the exhaust temperature sensor 76. For example, the gaseous substance may include but is not limited to steam, water vapor, grease particulates, smoke, aerosols and/or any other type of cooking by-product generated when the cooking units 18 are in operation that is to be exhausted by the fan 50 that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

Conventionally, the fan 50 operates at a constant velocity that is sufficient to exhaust the peak volumes of the gaseous substance when the cooking units 18 are in operation. For example, after the cooking units 18 are activated, the fan 50 operates at a constant velocity that is sufficient to exhaust the greatest volumes of gaseous substance that could be conceivably generated by the cooking units 18 for the duration of when the cooking units 18 are in operation. In doing so, the operation of the fan 50 at such a high constant velocity ensures that at during any window of operation of the cooking units 18, the gaseous substance is adequately exhausted despite the volume level of the gaseous substance. However, the cooking units 18 may not generate peak volumes of gaseous substances for the entire duration that the cooking units 18 are in operation. As a result, unnecessary energy is devoted to the fan 50 when the constant velocity with which the fan 50 is operating results in unnecessary increases in cost in maintaining the kitchen hood system 32.

Conventionally, the velocity with which the fan 50 operates can be adjusted based on the temperature of the kitchen hood system 32. The exhaust temperature sensor 76 monitors the temperature of the gaseous substance located within the exhaust hood 34. As the exhaust temperature sensor 76 detects a temperature of the gaseous substance that is within specified thresholds, the velocity of the fan 50 is then adjusted accordingly.

For example, conventionally the velocity of the fan 50 is increased when the temperature detected by the exhaust temperature sensor 76 exceeds a specified threshold indicating that an increased volume of the gaseous substance is located within the exhaust hood 34 and thus requiring that the fan 50 operate at higher velocities to adequately exhaust the gaseous substance. The velocity of the fan 50 is then conventionally decreased when the temperature detected by the exhaust temperature sensor 76 is below the specified threshold indicating that a decreased volume of the gaseous substance is located within the exhaust hood 34 and thus requires that the fan 50 operate at lower velocities to adequately exhaust the gaseous substance. The fan 50 is then conventionally deactivated when the exhaust temperature sensor 76 detects a temperature below a minimal threshold indicating that no gaseous substance is located within the exhaust hood 34 and thus the fan 50 is no longer required to operate.

However, the gaseous substance located within the exhaust hood 34 may not have a temperature that when detected by the exhaust temperature sensor 76 would trigger the fan 50 to increase its velocity to adequately exhaust the gaseous substance. Rather, the gaseous substance may be a gaseous substance such as steam that when present within the exhaust hood 34 would not have a temperature detected by the exhaust temperature sensor 76. The velocity of the fan 50 would then be inappropriately decreased based on the low temperature detected by the exhaust temperature sensor 76 due to the assumption that the low temperature is indicative of a decrease in the volume of the gaseous substance located within the exhaust hood 34. The fan 50 then fails to adequately exhaust the steam from the exhaust hood 34 because the fan 50 is operating at a lower velocity than is required to adequately exhaust the steam from the exhaust hood 34.

In addition to determining the volume of the gaseous substance located within the exhaust hood 34 based on temperature, the volume of the gaseous substance may also be correlated to the actual volume of the gaseous substance located within the exhaust hood 34. Sensing of the gaseous substance is accomplished with a gaseous substance sensor 82 by which to detect such gaseous substances that fail to generate a temperature sufficient to be detected by the exhaust temperature sensor 76 such as but not limited to water vapor, grease particulates, smoke and aerosols generated by the cooking units 18.

The gaseous substance sensor 82 is placed within the internal volume 46 of the exhaust hood 34, with a first optic sensor, such as an emitter 84, placed on one side wall 44 of the exhaust hood 34. The emitter 84 is powered over cable 85 and aligned to send a signal 86, such as a light beam, traversing a portion of the internal volume 46 along a light beam path to a second optic sensor, such as a detector 88, placed on an opposite side wall 44 of the exhaust hood 34.

The signal 86 may be any type of signal, such as a light beam, that when transmitted by the first optic sensor, such as the emitter 84, to the second optic sensor, such as the detector 88, that the magnitude of the signal 86 may be monitored by the control module 72 such that any fluctuations in the magnitude of the signal 86 may be adequately captured and analyzed that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure. Further, the first optic sensor and the second optic sensor may include any combination and/or any quantity of emitters and/or detectors so that the signal 86 is adequately transmitted and received so that the magnitude of the signal may be monitored by the control module 72 that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

Having the signal 86 traverse the longitudinal length of the exhaust hood 34 provides for an accurate measurement of the gaseous substance since the signal 86 passes above each of the plurality of cooking units 18 and just outside of the normal air flow path 52. The gaseous substance sensor 82 will output the gaseous substance signal 90 to the control module 72 corresponding to the level of the gaseous substance interrupting the signal 86. The control module 72 utilizes the gaseous substance signal 90 along with, or alternatively to, the heat level signal 78, to cause the control module 72 to initiate different graduated actions based on the gaseous substance signal 90. The different graduated actions may be actions initiated by the control module 72 within the kitchen hood system 32 that are in response to the heat level signal 78 and the gaseous substance signal 90.

In one embodiment of the present invention as shown in the cross-sectional view of the gaseous substance sensor 82 in FIG. 2, the control module 72 may monitor the magnitude of the signal 86 as the signal 86 traverses the longitudinal length of the exhaust hood 34 as transmitted from the emitter 84 and received by the detector 88. Fluctuations in the magnitude of the signal 86 may be indicative of activity within the exhaust hood 34, such as but not limited to the presence of the gaseous substance within the exhaust hood 34. Based on these fluctuations in the magnitude of the signal 86, the control module 72 may initiate graduated actions that when initiated ensure that the gaseous substance is adequately exhausted from the exhaust hood while minimizing the amount of energy devoted to the exhausting and thus reducing the overall amount of energy consumed by the kitchen hood system 32.

For example, the magnitude of the signal 86 may fluctuate based on the volume of the gaseous substance that is located within the exhaust hood 34. As the magnitude of the signal 86 decreases, this may be indicative that the volume of the gaseous substance has also increased. The increase in the volume of the gaseous substance may correspond to an increase in the density of the gaseous substance located between the emitter 84 and the detector 88. A reduction in the magnitude of the signal 86 may then result due to an increase in the density of the gaseous substance located between the emitter 84 and the detector 88. As a result, the control module 72 may monitor the magnitude of the signal 86 to determine that a drop in magnitude is indicative of an increase in the volume of the gaseous substance located within the exhaust hood 34.

As the magnitude of the signal 86 increases, this may be indicative that the volume of the gas substance has also deceased. The decrease in the volume of the gaseous substance may correspond to a decrease in the density of the gaseous substance located between the emitter 84 and the detector 88. An increase in the magnitude of the signal 86 may then result due to a decrease in the density of the gaseous substance located between the emitter 84 and the detector 88. As a result, the control module 72 may monitor the magnitude of the signal 86 to determine that an increase in magnitude is indicative of a decrease in the volume of the gaseous substance located within the exhaust hood 34.

In such an example, the control module 72 may initiate a graduated action in adjusting the velocity in which the fan 50 operates based on the magnitude of the signal 86. The control module 72 may increase the velocity in which the fan 50 operates as the magnitude of the signal 86 decreases because such a decrease in magnitude is indicative of an increase in the volume of the gaseous substance located in the exhaust hood 34, thus requiring that the fan 50 operate at higher velocities to adequately exhaust the gaseous substance.

The control module 72 may decrease the velocity in which the fan 50 operates as the magnitude of the signal 86 increases because such an increase in magnitude is indicative of a decrease in the volume of the gaseous substance located in the exhaust hood 34, thus requiring the fan 50 to operate at lower velocities to adequately exhaust the gaseous substance. The velocity of the fan 50 may then be customized to the volume of the gaseous substance located in the exhaust hood 34 so that the gaseous substance is adequately exhausted while preventing the devotion of unnecessary energy to operating the fan 50 at higher velocities than are necessary thus decreasing the amount of energy devoted to the exhausting as well as decreasing the overall amount of energy consumed by the kitchen hood system 32.

However, the magnitude of the signal 86 may be skewed due to fouling that accumulates on the emitter 84 and the detector 88. Fouling is the accumulation of unwanted material on solid surfaces to the detriment of function. Fouling may result due to the gaseous substance coming into contact with a lens 182 that is associated with the emitter 84 and a lens 184 that is associated with the detector 88. For example, grease and/or dust generated by the gaseous substance may accumulate on the lenses 182 and 184. As fouling accumulates on the lenses 182 and 184, the magnitude of the signal 86 is decreased in a similar fashion as the magnitude of the signal 86 decreases when the volume of the gaseous substance increases.

As a result, the control module 72 when monitoring the decrease in the magnitude of the signal 86 may incorrectly interpret such a decrease as an increase in the volume of the gaseous substance located in the exhaust hood 34. The control module 72 may then take graduated actions, such as increasing the velocity of the fan 50 to exhaust the increased volume of the gaseous substance, when in fact no such increase in the volume of the gaseous substance occurred. Unnecessary energy may then be devoted to the exhaust of the gaseous substance due to the unnecessary increase in the velocity of the fan 50 which then corresponds to an unnecessary increase in the overall cost of operating the kitchen hood system 32.

Fouling accumulation of the lenses 182 and 184 may occur each time that the gaseous substance comes into contact with the lenses 182 and 184. Even the slightest fouling accumulation may result in a decrease in the magnitude of the signal 86 such that the control module 72 incorrectly interprets the decrease as the presence of the gaseous substance. In order to properly remove the fouling accumulation of the lenses 182 and 184, the lenses 182 and 184 would have to be cleaned on a frequent basis which severely increases the maintenance associated with operating the kitchen hood system 32. Such an increase in maintenance results in a significant inconvenience to the operator to continually clean the lenses 182 and 184 as well as a significant increase in the overhead expenses associated with operating the kitchen hood system 32. Further, cleaning of the lenses 182 and 184 also increases the risk in abrasions to the lenses 182 and 184 which also trigger a decrease in the magnitude of the signal 86 such that the control module 72 incorrectly interprets the decrease as the presence of the gaseous substance.

Degradation in the magnitude of the signal 86 due to fouling accumulation may be mitigated by optics calibration for the gaseous substance sensor 82 by adjusting the intensity of the signal 86, such as the intensity of the light beam, from the emitter 84 to the detector 88. As will be discussed in more detail below, the automatic calibration of the gaseous substance sensor 82 may determine a baseline of the signal 86 in which the control module 72 may base any fluctuation in the magnitude of the signal 86 from that baseline to determine which if any graduated actions should be initiated. As the fouling accumulation increases, the magnitude of the signal 86 decreases. In performing the automatic calibration, the baseline of the signal 86 accounts for the decrease in the magnitude of the signal 86 due to the fouling accumulation so that any fluctuation in the magnitude of the signal 86 from that baseline may be indicative of the presence of the gaseous substance.

As a result, the control module 72 may refrain from initiating unnecessary graduated actions, such as increasing the velocity of the fan 50, due to the fouling accumulation so that the devotion of unnecessary energy to the kitchen hood system 32 may be prevented. As will be discussed in further detail below, the control module 72 may also initiate different graduated actions based on the fluctuation of the magnitude of the calibrated signal 86 so that the amount of energy devoted to the kitchen hood system 32 may be further reduced and thus reducing the cost associated with the operation of the kitchen hood system 32. Thus, the automatic calibration of the gaseous substance sensor 82 as well as the graduated actions initiated by the control module 72 provides the kitchen hood system 32 with low maintenance as well as with optimal energy savings throughout the operation of the kitchen hood system 32.

In one embodiment of the present invention, several different exhaust hoods 34 may be included within the same kitchen hood system 32. Each different exhaust hood 34 may encompass a different portion of cooking units 18. For example, a first exhaust hood 34 may encompass a first portion of cooking units 18 and then a second exhaust hood (not shown) may encompass a second portion of cooking units (not shown). However, both the first exhaust hood 34 and the second exhaust hood may be ducted together such that each different exhaust hood share the same duct 38 and fan 50. The control module 72 may control the fan 50 so that the fan 50 may adequately exhaust the gaseous substances from both the first exhaust hood 34 and the second exhaust hood while minimizing the amount of energy devoted to the fan 50 to exhaust the gaseous substances. A single gaseous substance sensor 82 may be monitored by the control module 72 to detect the volume of gaseous substances located in each of the first exhaust hood 34 and the second exhaust hood.

In such an embodiment, a single emitter 84 may be positioned on the first side wall 44 of the first exhaust hood 34 and a single detector 88 may be positioned on a second side wall (not shown) of the second exhaust hood. The positioning of the single emitter 84 and the single detector 88 may be done so that the signal 86 emitted by the single emitter 84 may traverse longitudinally from the single emitter 84 across both the internal volume (not shown) of the second exhaust hood as well as the internal volume 46 of the first exhaust hood 34 until reaching the single detector 88 located on the side wall 44 of the first exhaust hood.

The magnitude of the signal 86 may fluctuate based on the volume of gaseous substances located in both the first exhaust hood 34 and the second exhaust hood. Thus, the control module 72 may adjust the velocity of the fan 50 based on the fluctuation of the signal 86 so that the gaseous substances located in both the first exhaust hood 34 and the second exhaust hood may be adequately exhausted while minimizing the amount of unnecessary energy devoted to the exhaust of the gaseous substances. Any quantity of exhaust hoods may be ducted together to include a single duct 38 and a single fan 50 while being controlled by the control module 72 such that the signal 86 may be adequately transmitted by the single emitter 84 and received by the single detector 88 such that any fluctuation in the magnitude of the signal 86 may adequately represent the volumes of the gaseous substances located in each exhaust hood such that the control module 72 may adequately exhaust the gaseous substances while minimizing the amount of unnecessary energy devoted to the exhausting that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

In one embodiment of the present invention, several different exhaust hoods may be included in independent hood systems with each independent hood having an independent gaseous substance sensor that are each monitored by the control module 72. Each different exhaust system may be associated with a different portion of cooking units. For example, a first kitchen hood system 32 may be associated with a first portion of cooking units 18 where the first exhaust hood 34 encompasses the first portion of cooking units 18. A second hood system (not shown) similar to the first kitchen hood system 32 may be associated with a second portion of cooking units (not shown). The first kitchen hood system 32 is independent from the second hood system in that the first kitchen hood system 32 includes a first duct 38 as well as a first fan 50 while the second hood system includes a second duct (not shown) as well as a second fan (not shown).

The first kitchen hood system 32 also includes a first gaseous substance sensor 82 that is independent from a second gaseous substance sensor (not shown) that is included in the second hood system. The first gaseous substance sensor 82 emits a first signal 86 so that the magnitude of the signal 86 fluctuates based on the volume of the gaseous substance located within the first exhaust hood 34. The second gaseous substance sensor is positioned in a similar fashion as to the first gaseous substance sensor 82 with relation to the second exhaust hood so that the second signal (not shown) fluctuates based on the volume of the gaseous substance located within the second exhaust hood.

The control module 72 may then control the exhaust of the gaseous substance located within the first exhaust hood 34 independently from that of the gaseous substance located within the second exhaust hood. For example, the control module 72 may increase the velocity of the first fan 50 based on the first signal 86 generated from the first gaseous substance sensor 82 while decreasing the velocity of the second fan based on the second signal generated from the second gaseous substance sensor. As a result, the control module 72 may simultaneously control the first exhaust hood 34 and the second exhaust hood independent from each other so that the gaseous substances located in each are adequately exhausted while minimizing the amount of unnecessary energy devoted to the exhausting of each. Any quantity of exhaust systems may be independently controlled by the control module 72 such that the gaseous substance located in each exhaust system is adequately exhausted while minimizing the amount of unnecessary energy devoted to the exhaust of each that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

FIG. 3 illustrates an exhaust control system 33 in which embodiments of the present invention, or portions thereof, may be implemented. The exhaust control system 33 includes the control module 72, user interface 134, the gaseous substance sensor 82, the exhaust temperature sensor 76, the motor speed controller 70, and the auxiliary accessory controller 112. The control module 72 includes a microprocessor 130 and a memory 132.

In one embodiment of the present invention, one or more control modules 72 may connect to one or more modules that when commands are received by the control module 72, each module initiates a graduated action within the kitchen hood system 32 to adequately exhaust the gaseous substance located within the exhaust hood 34 while minimizing the amount of unnecessary energy devoted to the exhaust. The one or more modules may include temperature sensors, gaseous substance sensors, motor speed controllers, auxiliary accessory controllers and/or any other module that may initiate a graduated action within the exhaust system 32 to adequately exhaust the gaseous substance while minimizing the amount of energy devoted to the exhaust that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

The control module 72 includes a microprocessor 130 and a memory 132 and may be referred to as a computing device or simply “computer.” For example, the control module 72 may be a workstation, mobile device, computer, cluster of computers, set-top box, or other computing device. In one embodiment of the present invention, multiple modules may be implemented on the same computing device. Such a computing device may include software, firmware, hardware, or a combination thereof. Software may include one or more applications on an operating system. Hardware can include, but is not be limited to, microprocessor 130, the memory 132, and/or the user interface 134.

The control module 72 may communicate with each of the gaseous substance sensor 82, the exhaust temperature sensor 76, the motor speed controller 70, and the auxiliary accessory controller 112 via serial communication, wireless communication and/or a wired connection. Serial communication may be executed using serial semantics, such as RS45 multi-drop serial communication. However, any type of serial communication may be implemented that will be apparent from those skilled in the relevant art(s) without departing from the spirit and scope of the present disclosure.

Wireless communication may occur via one or more networks such as the internet. In some embodiments of the present invention, the network may include one or more wide area networks (WAN) or local area networks (LAN). The network may utilize one or more network technologies such as Ethernet, Fast Ethernet, Gigabit Ethernet, virtual private network (VPN), remote VPN access, a variant of IEEE 802.11 standard such as Wi-Fi, and the like. Communication over the network takes place using one or more network communication protocols including reliable streaming protocols such as transmission control protocol (TCP). These examples are illustrative and not intended to limit the present invention. Wired connection communication may occur with but is not limited to a fiber optic connection, a coaxial cable connection, a copper cable connection, and/or any other direct wired connection that will be apparent from those skilled in the relevant art(s) without departing from the spirit and scope of the present disclosure.

The user interface 134 may provide an operator the ability to interact with the control module 72. The user interface 134 may be any type of display device including but not limited to a touch screen display, a liquid crystal display (LCD) screen, and/or any other type of display that will be apparent from those skilled in the relevant art(s) without departing from the spirit and scope of the present disclosure.

As will be discussed in more detail below, the control module 72 may engage the gaseous substance sensor 82 so that the gaseous substance sensor 82 may be properly calibrated so that the signal 86 is at a magnitude that corresponds to the volume of the gaseous substance located within the exhaust hood 34. Automatically calibrating the gaseous substance sensor 82 so that the signal 86 is at a magnitude that corresponds to the volume of the gaseous substance may ensure that the graduated actions initiated by the control module 72 may adequately exhaust the gaseous substance from the exhaust hood 34 while refraining from initiating any unnecessary graduated actions that are not required to adequately exhaust the gaseous substance.

Referring now to FIG. 4, a flowchart is presented showing an exemplary process 400 for automatic calibration of the gaseous substance sensor 82 that may be executed by the control module 72 and the gaseous substance sensor 82. As noted above, the control module 72 may initiate an automatic calibration of the gaseous substance sensor 82 so that the signal 86 is at a magnitude that corresponds to the volume of the gaseous substance located in the exhaust hood 34 to mitigate the effects of fouling on the gaseous substance sensor 82.

The automatic calibration of the gaseous substance sensor 82 provides continuous monitoring of the kitchen hood system 32 so that the appropriate graduated actions may be taken at the appropriate times to ensure that the gaseous substance is adequately exhausted from the exhaust hood 34 while minimizing the amount of unnecessary energy devoted to the exhaust. As a result, the automatic calibration of the gaseous substance sensor 82 is not dependent upon specific events such as when the operator determines to manually calibrate the gaseous substance sensor 82 and/or when the kitchen hood system 32 is turned on and/or off. Limiting the calibration of the gaseous substance sensor 82 to specific events, such as when the hood system 32 is turned on and/or off, may result in decreases in the volume of the gaseous substance located within the exhaust hood 34 that occur between calibrations. However, such decreases are masked by fouling of the gaseous substance sensor 82 that results in a failure to decrease the velocity in the fan 50 despite a decrease in the volume of the gaseous substance located within the exhaust hood 34.

For example, limiting the calibration of the gaseous substance sensor 82 to occurring when the hood system 32 is turned on and/or off may result in several missed increases and/or decreases in the volume of the gaseous substance that is masked by fouling when the kitchen hood system 32 runs for days without being turned off. Thus, significant amounts of unnecessary energy may be devoted to the exhaust of the decreased volume of the gaseous substance for significant periods of time due to the fouling of the gaseous sensor decreasing the magnitude of the signal 86 during the significant period time that has lapsed between calibrations of the gaseous substance sensor 82.

Rather, the automatic calibration of the gaseous substance sensor 82 may not only calibrate at specified periods of time and/or when specified events occur but also when the gaseous substance is not present in the exhaust hood 34 as well as when events occur within the hood system 32 that may be indicative that an automatic calibration of the gaseous substance sensor 82 should occur. For example, the automatic calibration of the gaseous substance sensor 82 may occur every 24 hours as well as when the kitchen hood system 32 is turned on and/or off but the calibrating of the gaseous substance sensor 82 is not limited to calibration during these specified periods of time and/or specified events.

The automatic calibration of the gaseous substance sensor 82 may occur when the gaseous substance is not present in the exhaust hood 34 so that the calibration of the gaseous substance sensor 82 is not skewed by the presence of the gaseous substance. As noted above, the control module 72 may base any fluctuation in the magnitude of the signal 86 from the baseline determined from the automatic calibration of the gaseous substance sensor 82. However, a calibration of the gaseous substance sensor 82 when the gaseous substance is present in the exhaust hood 34 may affect the determined baseline in that the magnitude of the signal 86 may be decreased when the gaseous substance is present in the exhaust hood 34.

As a result, the baseline of the signal 86 may then be set unnecessarily low so that when the volume of the gaseous substance in the exhaust hood 34 changes, the control module 72 may base the fluctuation in the magnitude of the signal 86 inaccurately and unnecessarily initiate and/or fail to initiate graduated actions to adequately exhaust the gaseous substance while minimizing the amount of unnecessary energy devoted to the exhaust. Thus, the automatic calibration of the gaseous substance sensor 82 may not only occur at specified periods of time and/or after specified events, but also when the gaseous substance is not present in the exhaust hood 34 to improve the accuracy of the calibration.

The automatic calibration of the gaseous substance sensor 82 may also occur based on feedback received that is triggered during the operation of the kitchen hood system 32. As noted above, automatic calibration of the gaseous substance sensor 82 may occur after specified events, such as after the kitchen hood system 32 is turned on and/or off, where such specified events are planned in that the operator intentionally turns on and/or off the kitchen hood system 32.

However, other events that are unplanned and/or not easily observed by the operator may occur during operation of the kitchen hood system 32 that may require recalibration of the gaseous substance sensor 82 to ensure that the control module 72 monitors an accurate baseline of the signal 86. An automatic recalibration of the gaseous substance sensor 82 after an unplanned event occurs may enable the control module 72 to initiate the appropriate graduated action to adequately exhaust the exhaust hood 34 while minimizing the amount of unnecessary energy devoted to the exhaust.

In doing so, feedback signals may be generated after the occurrence of unplanned events that trigger the control module 72 to initiate the automatic calibration of the gaseous substance sensor 82. For example, a graduated action initiated by the control module 72 may include transitioning the fan 50 to an inactive mode in which the fan 50 is turned off to an active mode in which the fan 50 is turned on. The control module 72 may monitor the magnitude of the signal 86 and based on the magnitude of the signal 86, the control module 72 may activate the fan 50 accordingly. When a reduction in the magnitude of the signal 86 is greater than an activating threshold which indicates the likelihood of the gaseous substance located in the exhaust hood 34, the control module 72 may activate the fan 50 in response to the reduction in the magnitude of the signal 86 representing the presence of the gaseous substance located in the exhaust hood 34.

A feedback signal transmitted via a fan control signal 74 may then be automatically generated and received by the control module 72. The feedback signal may communicate to the control module 72 that the fan 50 has indeed been activated and trigger the control module 72 to recalibrate the gaseous substance sensor 82 to ensure that the gaseous substance is located in the exhaust hood 34 and activation of the fan 50 is required to adequately exhaust the gaseous substance.

A recalibration of the gaseous substance sensor 82 may confirm that the gaseous substance is located in the exhaust hood 34 and continued activation of the fan 50 is required to adequately exhaust the gaseous substance. A recalibration of the gaseous substance sensor 82 may also confirm that the gaseous substance is no longer located and/or the drop in the magnitude of the signal 86 was caused by something other than the gaseous substance being located in the exhaust hood 34. In response to such a confirmation, the control module 72 should initiate other graduated actions to minimize the amount of unnecessary energy devoted to the exhaust.

At step 410, the control module 72 may instruct the gaseous substance sensor 82 to initiate calibration via the gaseous substance signal 90. As noted above and also will be discussed below, the control module 72 may instruct the gaseous substance sensor 82 to initiate calibration based on the occurrence of any type of specified period of time, specified event, unplanned event, and/or any other parameter that may require the calibration of the gaseous substance sensor 82 so that the gaseous substance may be adequately exhausted while minimizing the amount of unnecessary energy devoted to the exhaust that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

At step 415, the control module 72 may determine whether the emitter 84 and the detector 88 are communicating. The control module 72 may instruct the emitter 84 and the detector 88 to engage in communication via the gaseous substance signal 90. In one embodiment of the present invention, the control module 72 may instruct the emitter 84 and the detector 88 to engage in serial communication. However, the emitter 84 and the detector 88 may engage in any type of communication so that the signal 86 may be adequately monitored by the control module 72 that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure. Step 415 may be performed continuously by the control module 72 when the gaseous substance sensor 82 is in operation to ensure that the detector 88 and the emitter 84 are communicating throughout such operation.

At step 420, a fault signal may be triggered when the emitter 84 and the detector 88 fail to communicate. The gaseous substance sensor 82 may transmit the fault signal via the gaseous substance signal 90 to the control module 72 when the emitter 84 and the detector 88 fail to communicate indicating that the emitter 84 and/or the detector 88 are not functioning properly and that the calibration of the gaseous substance sensor 82 cannot be completed.

At step 425, calibration of the gaseous substance sensor 82 may commence when communication between the emitter 84 and the detector 88 is established. During calibration of the gaseous substance sensor 82, an adequate baseline for the magnitude of the signal 86 may be determined. An adequate baseline of the signal 86 may be a magnitude that is within an optimal threshold. The optimal threshold may be a range of magnitudes in which the control module 72 may adequately monitor the magnitude of the signal 86 to determine which graduated actions should be initiated to adequately exhaust the gaseous substance while minimizing the amount of unnecessary energy devoted to the exhaust.

For example, the optimal threshold may be capped by a maximum voltage of 4V and a minimum voltage of 1V. An adequate baseline of the signal 86 may be obtained when the magnitude of the signal 86 is between 4V and 1V. The optimal threshold may be any range of values such that when the baseline of the signal 86 is within the optimal threshold so that the control module 72 may adequately monitor the magnitude of the signal 86 that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

As noted above, degradation in the magnitude of the signal 86 due to fouling accumulation may be mitigated by optics calibration for the gaseous substance sensor 82 by adjusting the magnitude of the signal 86 to establish a baseline of the signal 86 that is within the optimal threshold. As the hood system 32 operates, fouling accumulation increases which decreases the magnitude of the signal 86. Each time the gaseous substance sensor 82 is calibrated, a baseline of the signal 86 is established that is within the optimal threshold. The baseline of the calibrated signal 86 accounts for any decrease in the magnitude of the signal 86 due to fouling so such a decrease may be ignored by the control module 72. The control module 72 may then monitor the magnitude of the calibrated signal 86 to determine whether any fluctuations from the baseline of the calibrated signal 86 and then initiate graduated actions based on any fluctuation.

In establishing the baseline of the calibrated signal 86 so that the baseline is within the optimal threshold and accounts for any decrease in the magnitude due to fouling, the control module 72 may adjust the gain associated with the gaseous substance sensor 82. FIG. 5 illustrates an automatic calibration system 500 in which embodiments of the present invention, or portions thereof, may be implemented. The automatic calibration system 500 includes the control module 72, a gain module 520, and the emitter 84 and/or detector 82. The control module 72 includes the microprocessor 130 and the memory 132. The gain module 520 includes a plurality of gain settings 510(a-n), where n is an integer greater than one.

The control module 72 may request that the gaseous substance sensor 82 automatically calibrate via the output gaseous substance signal 90. The control module 72 may initially determine whether the current magnitude of the signal 86 is within the optimal threshold. If the current magnitude of the signal 86 is not within the optimal threshold, the control module 72 may then adjust the gain setting 510(a-n) of the gaseous substance sensor 82. In adjusting the gain setting 510(a-n) of the gaseous substance sensor 82, the magnitude of the signal 86 may be adjusted. The control module 72 may continue to adjust the gain setting 510(a-n) of the gaseous substance sensor 82 until the magnitude of the signal 86 is within the optimal threshold. At that point, the control module 72 may establish the magnitude of the signal 86 that is within the optimal threshold as the baseline in which to monitor.

For example, after a previous calibration, fouling may have accumulated on lenses 182 and 184 of the emitter 84 and the detector 88 and thus reducing the magnitude of the signal 86. In performing a subsequent automatic calibration of the gaseous substance sensor 82, the control module 72 may determine that the magnitude of the signal 86 is below the optimal threshold. Due to the accumulation of fouling, the magnitude of the signal 86 decreased to a level that may not be adequately monitored by the control module 72 to detect fluctuations in the magnitude. As a result, the control module 72 may increase the gain setting 510(a-n) in an attempt to increase the magnitude of the signal 86 so that the magnitude is within the optimal threshold. The control module 72 may continue to increase the gain setting 510(a-n) until the magnitude of the signal 86 is within the optimal threshold. At that point, the control module 72 may designate that magnitude as the baseline in which to monitor.

In an embodiment of the present invention, the gain module 520 may be a multiplexor so that when instructed by the control module 72, the multiplexor may select the gain setting 510(a-n) as specified by the control module 72. However, the gain module 520 may be any type of selecting device that is capable of selecting the necessary gain settings 510(a-n) as specified by the control module 72 that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

In an embodiment of the present invention, each gain setting 510(a-n) may be a resistor with a different resistance value so that when selected the change in resistance associated with each selected gain setting 510(a-n) may adjust the voltage level of the signal 86. However, each gain setting 510(a-n) may be any type of impedance component that when selected may change the magnitude of the signal 86 that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

Referring back to FIG. 4, the following steps provide an embodiment of the present invention in which the gain setting 510(a-n) may be adjusted in order to automatically calibrate the magnitude of the signal 86 so that the magnitude is within the optimal threshold to establish a baseline of the signal that may be adequately monitored by the control module 72.

After initial calibration has begun after step 425, in step 430, the control module 72 instructs the gain module 520 via the gaseous substance signal 90 a to select the gain setting 510 a which may include the highest gain value included in the gain module 520. In selecting the gain setting 510 a with the highest gain value, the magnitude of the signal 86 may be increased the greatest when the gain setting 510 a is applied to the signal 86. After the gain setting 510 a is applied to the signal 86, the control module 72 may monitor the magnitude of the signal 86 to determine if the magnitude is within the optimal threshold.

For example, the gain setting 510 a may include the highest resistance value included in the gain module 520 so that the voltage level of the signal 86 increases the greatest when the resistance value of the gain setting 510 a is applied to the signal 86. After the gain setting 510 a is applied to the signal 86, the control module 72 may determine whether the voltage level of the signal 86 is within the optimal threshold of 1V to 4V.

If the magnitude of the signal 86 is within the optimal threshold after the gain setting 510 a is applied, then in step 440, then calibration of the gaseous substance sensor 82 is completed. The baseline in which the control module 72 is to monitor for fluctuations is set at the current magnitude of the signal 86 in which the gain setting 510 a is applied and the emitter 84 emits the signal 86 at that magnitude. The control module 72 then monitors the signal 86 for fluctuations in the magnitude from the baseline. For example, the voltage level of the signal 86 after the resistance value included in the gain setting 510 a is applied to the signal 86 is 3.8V. 3.8V is within the optimal threshold of 1V to 4V. Thus, the control module 72 sets the baseline of the signal at 3.8V and the emitter 84 emits the signal 86 at a voltage of 3.8V. The control module 72 then monitors the baseline of 3.8V for any fluctuations.

If the magnitude of the signal 86 is still below the optimal threshold after the highest gain setting 510 a is applied to the signal 86, then in step 450, a feedback signal indicating an optic fault is triggered and sent to the control module 72 via the gaseous substance signal 90. After the highest gain setting 510 a is applied to the signal 86 and the magnitude of the signal 86 is still below the optimal threshold, then that is indicative that the emitter 84 and/or the detector 88 are not operating appropriately.

The magnitude of the signal 86 remaining below the optimal threshold after the highest gain setting 510 a is applied may be indicative that a significant amount of fouling has accumulated onto the lenses 182 and 184 resulting in a significantly low magnitude of the signal 86. Such a low magnitude may also be indicative that there is a blockage between the emitter 84 and the detector 88. The blockage may be an object or some other type of substance in which the fan 50 alone may not be able to remove.

After receiving the feedback signal indicating that the magnitude of the signal 86 is still below the optimal threshold despite the highest gain setting 510 a being applied, the control module 72 may instruct the gaseous substance sensor 82 to automatically recalibrate. In automatically recalibrating the gaseous substance sensor 82, the control module 72 may ensure that the emitter 84 and the detector 88 are indeed not operating appropriately and/or a blockage is present. For example, if after the automatic recalibration, the magnitude of the signal 86 is still below the optimal threshold, then there is an increased likelihood that there is an issue with the emitter 84 and/or the detector 88.

Regardless of the cause of the magnitude of the signal 86 falling below the optimal threshold after the highest gain setting 510 a is applied whether it be fouling and/or a blockage, having the fan 50 operate at a high velocity would result in unnecessary devotion of energy to exhausting the exhaust hood 34. As a result, the control module 72 may take the graduated action in reducing the velocity of the fan 50. The control module 72 may instruct the motor speed controller 70 via fan control signal 74 to reduce the velocity of the fan 50 so that unnecessary energy is not devoted to operating the fan 50 at a high velocity when such an operation would not remove the blockage and/or repair the emitter 84 and/or the detector 88. The control module 72 may also take the graduated action in instructing the user interface 134 via the user interface signal 136 to display an alert so that the operator may be aware of improper operation of the emitter 84 and/or detector 88 and/or of the potential blockage present in the exhaust hood 34.

If the magnitude of the signal 86 is greater than the optimal threshold despite the highest gain setting 510 a being applied, then in step 460, the next gain setting 510 b may be applied to the signal 86. The control module 72 may instruct the gain module 520 via the gaseous substance signal 90 b to apply the gain setting 510 b to the signal 86. The gain setting 510 b may have a gain value less than the gain value of the gain setting 510 a but greater than gain value of the gain setting 510 c. In selecting the gain setting 510 b, the magnitude of the signal 86 may be increased less than when the gain setting 510 a is applied to the signal 86 but more than when the gain setting 510 c is applied to the signal 86. After the gain setting 510 b is applied to the signal 86, the control module 72 may monitor the magnitude of the signal 86 to determine if the magnitude is within the optimal threshold.

For example, the gain setting 510 b may include a resistance value that is less than the resistance value of the gain setting 510 a but greater than the resistance value of the gain setting 510 b. After the gain setting 510 b is applied to the signal 86, the control module 72 may determine whether the voltage level of the signal 86 is within the optimal threshold of 1V to 4V.

If the magnitude of the signal 86 is within the optimal threshold after the gain setting 510 b is applied, then calibration of the gaseous substance sensor 82 is completed and the operational control flow moves to step 440 as discussed in detail above. However, if the magnitude of the signal 86 is still greater than the optimal threshold after the gain setting 510 b is applied, then in step 470, the next gain setting 510 c may be applied to the signal 86. The control module 72 may instruct the gain module 520 via the gaseous substance signal 90 c to apply the gain setting 510 c to the signal 86. The gain setting 510 c may have a gain value that is less than the gain value of the gain setting 510 b but greater than the gain value of the gain setting 510 n. After the gain setting 510 c is applied to the signal 86, the control module 72 may monitor the magnitude of the signal 86 to determine if the magnitude is within the optimal threshold.

If the magnitude of the signal 86 is within the optimal threshold after the gain setting 510 c is applied, then calibration of the gaseous substance sensor 82 is completed and the operational control flow moves to step 440 as discussed in detail above. However, if the magnitude of the signal 86 is still greater than the optimal threshold after the gain setting 510 c is applied, then in step 480, the next gain setting 510 n may be applied to the signal 86. The control module 72 may instruct the gain module 520 via the gaseous substance signal 90 n to apply the gain setting 510 n to the signal 86. The gain setting 510 n may have a gain value that is the lowest gain value of gain settings 510(a-n). After the gain setting 510 c is applied to the signal 86, the control module 72 may monitor the magnitude of the signal 86 to determine if the magnitude is within the optimal threshold.

If the magnitude of the signal 86 is within the optimal threshold after the gain setting 510 n is applied, then calibration of the gaseous substance sensor 82 is completed and the operational control flow moves to step 440 as discussed in detail above. However, if the magnitude of the signal 86 is still greater than the optimal threshold despite the lowest gain value in gain setting 510 n being applied to the signal 86, then in step 490, a feedback signal indicating an optic fault is triggered and sent to the control module 72 via the gaseous substance signal 90. After the lowest gain setting 510 n is applied to the signal 86 and the magnitude of the signal 86 is still above the optimal threshold, then that is indicative that the emitter 84 and/or the detector 88 are not operating appropriately.

After receiving the feedback signal indicating that the magnitude of the signal 86 is still above the optimal threshold despite the lowest gain setting 510 n being applied, the control module 72 may instruct the gaseous substance sensor 82 to automatically recalibrate. In automatically recalibrating the gaseous substance sensor 82, the control module 72 may ensure that the emitter 84 and the detector 88 are indeed not operating appropriately. For example, if after the automatic recalibration, the magnitude of the signal 86 is still above the optimal threshold, then there is an increased likelihood that there is an issue with the detector 88 and/or the emitter 84. The control module 72 may then take the graduated action in instructing the user interface 134 via user interface signal 136 to display an alert so that the operator may be aware of improper operation of the emitter 84 and/or detector 88.

As noted above, steps 430-490 are an embodiment of the present invention. However, other embodiments may entail applying a lowest gain setting to the signal 86 first and then incrementally increasing the gain setting applied to the signal 86 until magnitude of the signal 86 is within the optimal threshold. Any type of method in applying different gain settings to the signal 86 in attempt to adjust the magnitude of the signal 86 so that the magnitude is within the optimal threshold may be implemented that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

As noted above, after calibration of the signal 86 is completed in step 440, then in step 495, the magnitude of the signal 86 may be monitored by the control module 72 for fluctuations in the magnitude of the signal 86 from the baseline selected during calibration. Fluctuations in the magnitude of the signal 86 from the baseline may be indicative that graduated actions should be initiated by the control module 72 to adequately exhaust any gaseous substance located in the exhaust hood 34 while minimizing the amount of unnecessary energy devoted to the exhaust. Examples of the type of monitoring done by the control module 72 of the magnitude of the signal 86 and graduated actions initiated by the control module 72 based on that monitoring will be discussed in further detail below.

Referring now to FIG. 6, a flowchart is presented showing an exemplary process 600 for transitioning the fan 50 between an inactive mode and an active mode that may be initiated by the control module 72 and the motor speed controller 70. After the signal 86 has been calibrated, the control module 72 may monitor the magnitude of the signal 86 to determine if fluctuations in the magnitude of the signal 86 from the baseline set during calibration occur. Based on this monitoring, the control module 72 may initiate graduated actions by instructing the motor speed controller 70 to activate or deactivate the fan 50 accordingly.

In step 610, the control module 72 monitors the signal 86 to determine whether a reduction in the magnitude of the signal 86 is greater than the activating threshold. The activating threshold is the level of reduction in the magnitude of the signal 86 that when reached by the magnitude of the signal 86 indicates that the gaseous substance is located in the exhaust hood 34 and that activation of the fan 50 should occur.

If the reduction in the magnitude of the signal 86 is less than the activating threshold, then in step 620, the control module 72 refrains from instructing the motor speed controller 70 to transition the fan 50 into the active mode and continues to monitor the magnitude for any fluctuations from the baseline. The reduction in the magnitude of the signal 86 being less than the activating threshold may indicate that the gaseous substance is not located in the exhaust hood 34 and thus not requiring that the fan 50 be transitioned into the active mode to exhaust the gaseous substance. As noted above, the presence of the gaseous substance may result in a reduction in the magnitude of the signal 86 from the baseline. However, the magnitude of the signal 86 may not be reduced from the baseline when the gaseous substance is not present in the exhaust hood 34.

If the reduction in the magnitude of the signal 86 is greater than the activating threshold, then in step 630, the control module 72 determines whether the reduction in the magnitude of the signal is less than a blocking threshold. The blocking threshold is the level of reduction in the magnitude of the signal 86 that when reached indicates that blockage is present between the emitter 84 and the detector 88 rather than the gaseous substance. The blockage present between the emitter 84 and the detector 88 may cause the magnitude of the signal 86 to decrease significantly as compared to the decrease in the magnitude of the signal 86 that may result from the gaseous substance being located in the exhaust hood 34.

If the reduction in the magnitude of the signal is greater than the blockage threshold, then the operational control flow returns to step in step 620, the control module 72 may refrain from instructing the motor speed controller 70 to transition the fan 50 into the active mode. As noted above, any type of blockage may not be removed by activating the fan 50 so any such activation would be an unnecessary devotion of energy. Thus, the control module 72 may refrain from instructing any such activation.

If the reduction in the magnitude of the signal 86 is less than the blockage threshold but greater than the activating threshold, then in step 640, the control module 72 may instruct the motor speed controller 70 via the fan control signal 74 to transition the fan 50 from the inactive mode to the active mode. As noted above, the reduction in the magnitude of the signal 86 that is greater than the activating threshold but less than the blockage threshold indicates that there is an increased likelihood that the gaseous substance is now located in the exhaust hood 34. The activation of the fan 50 is then necessary to adequately exhaust the gaseous substance from the exhaust hood 34 and the control module 72 initiates such a graduated action accordingly.

For example, the baseline for the magnitude of the signal 86 after calibration is 3.8V. The activating threshold indicating that the gaseous substance is located in the exhaust hood 34 is when the magnitude of the signal 86 is reduced by 10%, or by 0.38V in this example. The blockage threshold indicating that a blockage is located in the exhaust hood 34 and not the gaseous substance is when the magnitude of the signal 86 is reduced by 80% or by 3.04V in this example. The magnitude of the signal 86 decreases from 3.8V to 3V. Such a decrease is greater than the activating threshold of 0.38V but less than the blockage threshold of 3.04V. As a result, the control module 72 instructs the motor speed controller 70 to transition the fan 50 from the inactive mode to the active mode.

In step 650, a feedback signal may be triggered indicating that the fan 50 has indeed been transitioned from the inactive mode to the active mode and sent to the control module 72 via the fan control signal 74. The control module 72 may then instruct the gaseous substance sensor 82 via the gaseous substance signal 90 to recalibrate. The transitioning of the fan 50 from the inactive mode to the active mode is a significant devotion of energy. Before initiating such a significant devotion of energy for an extended period of time, the control module 72 may initiate the graduated action of automatic recalibration of the gaseous substance sensor 82 to ensure that the gaseous substance is indeed located in the exhaust hood 34 and that activation of the fan 50 is proper to adequately exhaust the gaseous substance from the exhaust hood 34.

If the magnitude of the signal 86 after the automatic recalibration is similar to the previous magnitude after the previous reduction had occurred, then presence of the gaseous substance in the exhaust hood 34 is likely. The control module 72 may then instruct the motor speed controller 70 to continue to maintain the fan 50 in the active mode. However, if the magnitude of the signal 86 has increased from the magnitude after the previous reduction, then the presence of the gaseous substance in the exhaust hood is not likely. The control module 72 may then instruct the motor speed controller 70 via the fan control signal 74 to transition the fan 50 from the active mode to the inactive mode to deactivate the fan 50 because activation of the fan 50 is not necessary.

Referring now to FIG. 7, a flowchart is presented showing an exemplary process 700 by which the control module 72 may adjust the velocity of the fan 50 based on the presence of the gaseous substance even if the temperature data does not indicate that the velocity of the fan 50 should be adjusted. After the signal 86 has been calibrated, the control module 72 may monitor the magnitude of the signal 86 to determine if fluctuations in the magnitude of the signal 86 from the baseline set during calibration occur. Based on this monitoring, the control module 72 may initiate graduated actions by instructing the motor speed controller 70 to adjust the velocity of the fan 50 accordingly.

Fan 50 is operated, in step 710, based on the magnitude of the signal 86. In step 720, the control module 72 monitors the gaseous substance sensor 82 within the exhaust hood 34 to determine if it indicates the presence of the gaseous substance. The control module 72 determines, in step 730, whether the gaseous substance sensor 82 indicates that there has been a noticeable reduction in the transmitted light of the signal 86. For example, a 5% reduction is one possible threshold at which to decide that corrective action is necessary. Otherwise, the control module 72 continues to monitor the gaseous substance sensor 82, in step 720.

In step 740, the control module 72 tests the density of the gaseous substance a second time approximately one second after step 730 to determine whether the gaseous substance is present. By performing step 740 in this manner, the control module 72 may determine if the presence of the gaseous substance still exists and, further, the control module 72 may recognize the duration in which the gaseous substance has been present. If the gaseous substance is still present, then the control module 72 adjusts the velocity of the fan 50 in step 780. If no gaseous substance is present, then the gaseous substance has dissipated and control of the velocity of the fan 50 by the control module 72 can once again be based on exhaust air temperature. However, as a precaution, the fan 50 is operated at its current velocity, in step 760, for a preset time period to ensure all the gaseous substance has been successfully dissipated. An exemplary time period is one minute but the fan 50 may operate in this manner for a period ranging from a few seconds to over a minute.

The adjusting of the velocity of the fan 50, in step 780, may be performed in accordance with the following table:

Elapsed Time ≧5% ≧7% ≧9% 1 s 60% 80% 100% 2 s 80% 100% 100% 3 s 100% 100% 100%

If the desired velocity of the fan 50, determined according to one of the exhaust temperature control algorithms, is greater than an entry within the above table, this gaseous substance control algorithm may not decrease the velocity of the fan 50 as doing so would worsen the conditions in the exhaust hood.

If, upon reaching step 780 the first time, the control module 72 detects that the light reduction remains greater than 5%, then a velocity is selected from the first row of the table based on the detected percentage of light reduction. After adjusting the velocity in step 780, the control module 72 returns to step 740 and by now two seconds have elapsed. If the light reduction in the signal 86 remains greater than 5%, then a velocity is selected from the second row of the table. If the gaseous substance has dissipated, however, the control module 72 operates the fan 50 according to step 760 as explained above.

If the control module 72 returns once again to step 740, three seconds have elapsed and if the gaseous substance persists, then a velocity is selected from the third row of the table. Once step 740 is performed three times, the velocity is at 100% regardless of the exact amount of light reduction detected in the signal 86. Thus, step 740 can be repeated over and over again until the gaseous substance dissipates and operational control flow passes to step 760 but on these subsequent iterations, no new speed is selected from the table as the fan 50 is already being operated at their maximum speed. Thus, both the duration and intensity of the gaseous substance is within the exhaust hood 34 is used to select a fan speed to help dissipate the smoke.

Referring now to FIG. 8, a flowchart is presented showing an exemplary process 800 detecting a blockage located in the exhaust hood 34 and initiating the appropriate graduated actions so that unnecessary energy in operating the fan 50 is not devoted to attempting to remove the blockage. After the signal 86 has been calibrated, the control module 72 may monitor the magnitude of the signal 86 to determine if fluctuations in the magnitude of the signal 86 from the baseline set during calibration occur. Based on this monitoring, the control module 72 may initiate graduated actions by instructing the motor speed controller 70 to control the fan 50 based on the temperature of the exhaust hood 34 rather than the magnitude of the signal 86.

In step 810, the control module 72 monitors the signal 86 to determine whether a reduction in the magnitude of the signal 86 is greater than a permanent blockage threshold and longer than a blockage time period. The permanent blockage threshold is the level of reduction in the magnitude of the signal 86 that when reached by the magnitude of the signal 86 for longer than the blockage period of time indicates a blockage is causing the reduction in the magnitude of the signal 86 rather than the gaseous substance.

As noted above, a blockage located between the emitter 84 and the detector 88 may result in a significantly greater reduction in the magnitude of the signal 86 from the baseline as compared to a reduction caused by the gaseous substance. As such a significant reduction continues for an extended period of time, such as longer than the blockage period of time, the likelihood that the cause of the significant reduction in the magnitude of the signal 86 is a blockage rather than the gaseous substance increases.

If the reduction in the magnitude of the signal 86 is less than the permanent blockage threshold and/or such a reduction does not extend beyond the blockage period of time, then in step 820, the control module 72 ignores the temporary reduction and continues to monitor the magnitude of the signal 86. Any type of reduction in the magnitude of the signal 86 that is less than the permanent blockage threshold and/or does not extend beyond the blockage period of time may be indicative that a blockage is not present in the exhaust hood 34.

If the reduction in the magnitude of the signal 86 is greater than the permanent blockage threshold and such a reduction extends beyond the permanent blockage period of time, then in step 830, a feedback signal is generated and sent to the control module 72 from the gaseous substance sensor 82 via the gaseous substance signal 90. Based on this feedback signal, the control module 72 may then instruct the gaseous substance sensor 82 to recalibrate via the gaseous substance signal 90.

The potential presence of the blockage in the exhaust hood 34 may result in graduated actions taken by the control module 72 that may reduce the amount of energy devoted to the exhaust of the exhaust hood 34. A reduction in the amount of energy devoted to the exhaust in turn may result in decreasing the capabilities of the exhaust hood system 32 from adequately exhausting the exhaust hood 34. For example, the control module 72 may reduce the velocity of the fan 50 when the blockage is present because the fan 50 may have minimal impact on removing the blockage. However, reducing the fan 50 may also have a reduced impact on adequately exhausting the gaseous substance from the exhaust hood 34. As a result, the control module 72 may instruct the gaseous substance sensor 82 to recalibrate to ensure that the significant reduction in the magnitude of the signal 86 continues.

In step 840, the control module 72 determines whether a reduction in the magnitude of the recalibrated signal 86 is still greater than the permanent blockage threshold and has lasted longer than the blockage period of time.

If the reduction in the magnitude of the signal changes and is no longer greater than the permanent blockage threshold and/or extends longer than the blockage period of time, then the operational control flow returns to in step 820, the control module 72 ignores the temporary reduction and continues to monitor the magnitude of the signal 86.

If the reduction in the magnitude of the signal 86 is greater than the permanent blockage threshold and extends longer than the blockage period of time, then in step 850, the control module 72 may instruct the exhaust temperature sensor 76 to adjust the temperature span as well as instruct the user interface 134 to display an optic fault to the operator. Despite the presence of the blockage in the exhaust hood 34, the gaseous substance may be present in the exhaust hood 34 as well. As noted above, the presence of the blockage may result in a significant reduction in the magnitude of the signal that is significantly less than a reduction caused by the presence of the gaseous substance. Thus, the control module 72 may no longer monitor the magnitude of the signal 86 for fluctuations to initiate the necessary graduated actions to adequately exhaust the gaseous substance while minimizing the amount of unnecessary energy devoted to the exhaust.

Rather, the control module 72 may be limited to relying on the temperature of the exhaust hood 34 to determine which graduated actions to initiate to adequately exhaust the gaseous substance. As a result, the control module 72 may initiate the graduated action of instructing the exhaust temperature sensor 76 to reduce the temperature span via the heat level signal 78. As noted above, gaseous substances, such as steam, may not generate the heat associated with other gaseous substances, such as gases. In order to still exhaust the gaseous substances despite not being able to monitor the magnitude of the signal 86, the control module 72 may instruct the exhaust temperature sensor 76 to lower the temperature span. In lowering the temperature span, the presence of gaseous substances with lower temperatures in the exhaust hood 34 may be detected by the control module 72 so that the control module 72 may initiate graduated actions to still exhaust the gaseous substance to some extent.

For example, the baseline for the magnitude of the signal after an initial calibration is 3.8V. The permanent blockage threshold indicating that a blockage is located in the exhaust hood 34 is when the magnitude of the signal 86 is reduced by 80%, or 3.04V in this example, for longer than the blockage period of time which is 10 minutes. The magnitude of the signal 86 decreases from 3.8V to 0.02V for longer than 10 minutes. As a result, the control module 72 instructs the exhaust temperature sensor 76 to reduce the temperature span to 75 degrees (F) to 90 degrees (F). The control module 72 may then initiate any graduated actions to exhaust the gaseous substance when the temperature of the exhaust hood 34 falls within 75 degrees (F) and 90 degrees (F). The control module 72 also instructs the user interface 134 via the user interface signal 136 to display an optical fault to the operator so that the operator is aware of the blockage located in the exhaust hood 34.

Referring now to FIG. 9, a flowchart is presented showing an exemplary process 900 determining whether auxiliary accessories associated with the exhaust of the gaseous substance from the exhaust hood 34 may be deactivated when activation of the auxiliary accessories is not necessary. After the signal 86 has been calibrated, the control module 72 may monitor the magnitude of the signal 86 to determine if a minimum reduction, if any, in the magnitude of the signal 86 has occurred indicating that the gaseous substance is not located in the exhaust hood 34. Based on this monitoring, the control module 72 may initiate graduated actions by instructing the auxiliary accessory controller 112 to deactivate the auxiliary accessories that are no longer necessary with the gaseous substance gone from the exhaust hood 34.

An auxiliary accessory may be an accessory in addition to the fan 50 that when in operation may contribute to the adequate exhaust of the gaseous substance. For example, auxiliary accessories may include but are not limited to ultraviolet (UV) lamps and electrostatic precipitators that are used to remove grease from the exhaust hood 34, the duct 38, and the airstream. Other auxiliary accessories that when activated contribute to the adequate exhaust of the gaseous substance may be deactivated to reduce the amount of unnecessary energy devoted to the kitchen hood system 32 that will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the disclosure.

In step 910, the control module 72 monitors the signal 86 to determine whether a reduction in the magnitude of the signal is less than an auxiliary accessory threshold for greater than an auxiliary accessory period of time. The auxiliary accessory threshold is a minimum level of reduction in the magnitude of the signal 86 that when maintained for longer than the auxiliary accessory period of time indicates that the gaseous substance is not located in the exhaust hood 34 and thus causing such a minimum reduction in the magnitude of the signal 86.

As noted above, the lack of the gaseous substance located in the exhaust hood 34 may result in a minimum, if any, reduction in the magnitude of the signal 86 from the baseline as compared to a reduction caused by the gaseous substance. As such a minimum reduction continues for an extended period of time, such as longer than the auxiliary accessory period of time, the likelihood that the there is no presence of the gaseous substance in the exhaust hood 34 increases.

If the reduction in the magnitude of the signal 86 is greater than the auxiliary accessory threshold, then in step 920, the control module 72 continues to maintain each of the auxiliary accessories in the active mode and continues to monitor the magnitude of the signal 86. A reduction in the magnitude of the signal 86 that is greater than the auxiliary accessory threshold and extends beyond the auxiliary accessory period of time is indicative that the gaseous substance is located in the exhaust hood 34 and that the activation of the auxiliary accessories is necessary to adequately exhaust the gaseous substance.

If the reduction in the magnitude of the signal 86 is less than the auxiliary accessory threshold and such a minimum reduction extends beyond the auxiliary accessory period of time, then in step 840, the control module 72 instructs the auxiliary accessory controller 112 via an auxiliary accessory signal 102 to transition the auxiliary accessories no longer necessary to exhaust the gaseous substance from the active mode to the inactive mode.

The lack of the gaseous substance in the exhaust hood 34 may result in graduated actions taken by the control module 72 to reduce the amount of energy devoted to the exhaust of the exhaust hood 34. Auxiliary accessories, such as the UV lights, fail to provide any additional contribution to the kitchen hood system 32 when exhausting the gaseous substance is no longer necessary. Thus, the operation of the UV lights in the active mode is simply a devotion of unnecessary energy to the operation of the kitchen hood system 32 and may be transitioned into the inactive mode to prevent the devotion of such unnecessary energy. As a result, the control module 72 may instruct the auxiliary accessory controller 112 to transition the UV lights from the active mode to the inactive mode.

In step 940, the control module 72 monitors the signal 86 to determine whether a reduction in the magnitude of the signal 86 is greater than an auxiliary accessory activation threshold. The auxiliary accessory activation threshold is the level of reduction in the magnitude of the signal 86 that is indicative that the gaseous substance is located in the exhaust hood 34 requiring the activation of each of the auxiliary accessories to adequately exhaust the gaseous substance.

If the reduction in the magnitude of the signal 86 continues to be less than the auxiliary accessory activation threshold, then the operational control flow continues to step 950, the control module 72 continues to maintain each of the auxiliary accessories in the inactive mode and continues to monitor the magnitude of the signal 86.

If the reduction in the magnitude of the signal 86 increases to be greater than the auxiliary accessory activation threshold, then in step 960, the control module 72 may instruct the auxiliary accessory controller 112 via the auxiliary accessory signal 102 to transition auxiliary accessories from the inactive mode to the active mode. The increased reduction in the magnitude of the signal 86 to be greater than the auxiliary accessory activation threshold may be indicative that the gaseous substance is located in the exhaust hood 34 and thus requiring the activation of the auxiliary accessories to adequately exhaust the gaseous substance.

For example, the baseline for the magnitude of the signal 86 after an initial calibration is 3.8V. The auxiliary accessory threshold indicating that the gaseous substance not located in the exhaust hood 34 when the magnitude of the signal 86 is reduced by less than 5%, or 0.19V in this example, for longer than the auxiliary accessory period of time which is 5 minutes. The magnitude of the signal 86 is maintained at 3.8V for longer than 5 minutes. As a result, the control module 72 instructs the auxiliary accessory controller 112 to deactivate the auxiliary accessories no longer required to exhaust the gaseous substance.

The control module 72 continues to monitor the magnitude of the signal 86 to identify when the magnitude of the signal 86 is reduced greater than the auxiliary accessory activation threshold of 7%, or 0.27V in this example. The magnitude of the signal 86 is reduced to 3.5V indicating that the gaseous substance is now located in the exhaust hood 34. As a result, the control module 72 instructs the auxiliary accessory controller 112 to activate the auxiliary accessories to adequately exhaust the gaseous substance.

Referring now to FIG. 10, a flowchart is presented showing an exemplary process 1000 determining when recalibration of the signal 86 should occur. After the signal 86 has been calibrated, the control module 72 may recalibrate the signal 86 after specified actions have occurred to ensure that the magnitude of the signal 86 has not been adjusted after the specified actions have been initiated. The control module 72 may then initiate graduated actions based on the recalibrated signal 86 that may include but are not limited terminating the specified actions because those specified actions are no longer necessary after evaluating the magnitude of the signal 86 after recalibration.

In step 1010, the control module 72 determines whether the fan 50 has been operating in the active mode for longer than an active mode period of time. Often times, the fan 50 may operate in the active mode continuously for long periods of time without transitioning to the inactive mode. If the control module 72 were to wait until the fan 50 transitions between the active mode to the inactive mode to recalibrate the gaseous substance sensor 82, the control module 72 may miss several instances where the gaseous substance was located in the exhaust hood 34 but was masked due to fouling of the emitter 84 and/or detector 88. Thus, the active mode period of time is a lengthy period of time that when lapsed without having the fan 50 transition between the active mode and the inactive mode triggers the control module 72 to recalibrate the gaseous substance sensor 82. For example, the active mode period of time may lapse when the fan 50 operates in the active mode for 24 continuous hours.

If the fan 50 has not been operating in the active mode for longer than the active mode period of time, then in step 1020, the control module 72 continues to monitor the magnitude of the signal 86.

If the fan 50 has been operating in the active mode for longer than the active mode period of time, then in step 1030, a feedback signal may be triggered signifying that the fan 50 has indeed been operating in the active mode for longer than the active mode period of time and sent to the control module 72 via the fan control signal 74. As noted above, after the fan 50 has been operating in the active mode for an extended period of time, the gaseous substance sensor 82 should be recalibrated to account for any fouling that has occurred during the extended period of time. Thus, the feedback signal triggers the control module 72 to instruct the gaseous substance sensor 82 via the gaseous substance signal 90 to recalibrate.

As noted above, the automatic calibration of the gaseous substance sensor 82 may occur when the gaseous substance is not present in the exhaust hood 34 so that the calibration of the gaseous substance sensor 82 is not skewed by the presence of the gaseous substance. As a result, in step 1040, the control module 72 may monitor the signal 86 to determine whether the reduction in the magnitude of the signal 86 after the fan 50 has been operating in the active mode for longer than the active mode period of time is greater than a gaseous substance detection threshold. The gaseous substance detection threshold is the reduction in the magnitude of the signal 86 that when reached is indicative that the gaseous substance is located in the exhaust hood 34 and as a result, recalibration should not occur.

If the reduction in the magnitude of the signal 86 is less than the gaseous substance detection threshold, then in step 1050, the control module 72 may initiate the graduating action to instruct the gaseous substance sensor 82 to recalibrate via the gaseous substance signal 90. The reduction in the magnitude of the signal 86 being less than the gaseous substance detection threshold is indicative that the gaseous substance is not located in the exhaust hood 34 and that recalibration may commence.

If the reduction in the magnitude of the signal 86 is greater than the gaseous substance detection threshold, then in step 1060, the control module 72 may refrain from instructing the gaseous substance sensor 82 to recalibrate. The reduction in the magnitude of the signal 86 being greater than the gaseous substance detection threshold is indicative that the gaseous substance is located in the exhaust duct and that recalibration should not commence.

In step 1070, the control module 72 may determine whether an additional kitchen hood system (not shown) has been transitioned into the active mode in addition to the kitchen hood system 32 already in operation.

If the additional kitchen hood system has not been transitioned into the active mode, then the operational control flow returns to step 1020 and the control module 72 may continue to monitor the magnitude of the signal 86.

If the additional kitchen hood system has been transitioned in the active mode, then the operational control flow returns to step 1030, and a feedback signal may be triggered that the additional kitchen hood system 32 has indeed been activated. The activation of the additional kitchen hood system is a significant devotion of energy to the exhaust of the gaseous substance. The gaseous substance sensor 82 may be recalibrated to ensure that any significant reductions in the magnitude of the signal 86 indeed indicates that activation of the additional kitchen hood system is necessary to adequately exhaust the gaseous substance. Thus, the feedback signal triggers the control module 72 to instruct the gaseous substance sensor 82 via the gaseous substance signal 90 to recalibrate.

The operational control flow then proceeds through steps 1040-1060 as discussed above to determine whether the gaseous substance is located in the exhaust hood 34 in order to recalibrate the gaseous substance sensor 82.

In step 1080, the control module 72 may determine whether the magnitude of the signal 86 has increased beyond an increase threshold of the current baseline of the signal 86. The increase threshold is the increase in the magnitude of the signal 86 that when reached is indicative that the gaseous substance that was previously located in the exhaust hood 34 is no longer present.

If the magnitude of the signal 86 has not increased beyond the increase threshold, then the operational control flow returns to step 1020 and the control module 72 may monitor the magnitude of the signal 86.

If the magnitude of the signal 86 has increased beyond the increase threshold, then in step 1090, a feedback signal may be triggered that the gaseous substance is no longer located in the exhaust hood 34 and that the recalibration of the gaseous substance sensor 82 should commence. Thus, the feedback signal triggers the control module 72 to instruct the gaseous substance sensor 82 via the gaseous substance signal 90 to recalibrate.

While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details of the representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicants' general inventive concept. 

What is claimed is:
 1. A computer implemented method for calibrating and monitoring at least one optic sensor associated with at least one kitchen hood system, comprising: emitting a signal by a first optic sensor; receiving the signal by the second optic sensor that is in alignment with the first optic sensor; calibrating, by a controller, a magnitude of the signal by adjusting a gain associated with the signal until the magnitude of the signal is within an optimal threshold; monitoring, by the controller, the magnitude of the calibrated signal for fluctuations in the magnitude of the calibrated signal beyond at least one specified threshold; and initiating, by the controller, the at least one graduated action when the magnitude of the calibrated signal fluctuates beyond the at least one specified threshold, wherein the at least one graduated action reduces an overall amount of energy consumed by the at least one kitchen hood system and/or recalibrates the magnitude of the signal.
 2. The computer implemented method of claim 1, wherein the calibrating of the magnitude of the signal comprises: selecting an initial baseline when the magnitude of the signal is initially calibrated to be within the optimal threshold so that the initial baseline is the magnitude of the signal adjusted when initially calibrated, wherein an at least one graduated action is initiated relative to the initial baseline; and automatically adjusting the initial baseline to a recalibrated baseline when the magnitude of the signal is adjusted to be within the optimal threshold during a recalibration of the magnitude of the signal after an initial calibration of the signal is completed, wherein the at least one graduated action is initiated relative to the recalibrated baseline.
 3. The computer implemented method of claim 2, further comprising: recalibrating the magnitude of the signal to the recalibrated baseline when the magnitude of the signal fluctuates beyond the optimal threshold to account for fouling to the at least one optic sensor.
 4. The computer implemented method of claim 1, wherein calibrating the magnitude of the signal comprises: automatically adjusting the gain to a first gain setting from a plurality of gain settings when the magnitude of the signal is outside the optimal threshold; and continuing to automatically adjust the gain to a different gain setting from the plurality of gain settings until the magnitude of the signal is within the optimal threshold.
 5. The computer implemented method of claim 4, wherein calibrating the magnitude of the signal further comprises: measuring a signal level associated with the magnitude of the signal, wherein the signal level is indicative of a magnitude of light in the signal being transmitted from the first optic sensor to the second optic sensor; determining whether the signal level is within the optimal threshold, wherein the optimal threshold is a range of signal levels within a first signal level and a second signal level; automatically adjusting the gain to the first gain setting from the plurality of gain settings when the signal level is outside the range of signal levels associated with the optimal threshold; and continuing to automatically adjust the gain to the different gain setting from the plurality of gain settings until the signal level is within the range of signal levels associated with the optimal threshold.
 6. The computer implemented method of claim 4, wherein calibrating the magnitude of the signal further comprises: generating a fault signal when the gain is adjusted to each gain setting included in the plurality of gain settings and the magnitude of the signal is outside the optimal threshold.
 7. The computer implemented method of claim 1, wherein monitoring the calibrated signal comprises: monitoring the magnitude of the calibrated signal for a reduction in the magnitude of the calibrated signal that is greater than an activating threshold before at least one fan associated with the at least one kitchen hood system is in an active mode, wherein the reduction in the magnitude of the calibrated signal that is greater than the activating threshold indicates a gaseous substance is present in the at least one kitchen hood system.
 8. The computer implemented method of claim 7, wherein initiating at least one graduated action comprises: initiating an activation graduated action to transition an at least one fan associated with the at least one kitchen hood system into the active mode when the reduction in the magnitude of the calibrated signal is greater than the activating threshold.
 9. The computer implemented method of claim 8, wherein initiating the at least one graduated action further comprises: initiating a deactivation graduated action to maintain the at least one fan associated with the at least one kitchen hood system in an inactive mode when the reduction in the magnitude of the calibrated signal is less than the activating threshold indicating that the gaseous substance is not present in the at least one kitchen hood system.
 10. The computer implemented method of claim 9, wherein initiating the at least one graduated action further comprises: initiating the deactivation graduated action to maintain the at least one fan associated with the at least one kitchen hood system in the inactive mode when the reduction in the magnitude of the calibrated signal is greater than a blockage threshold indicating that a blockage is present in the at least one kitchen hood system.
 11. The computer implemented method of claim 1, wherein monitoring the calibrated signal further comprises: monitoring the magnitude of the calibrated signal for a reduction in the magnitude of the calibrated signal that is greater than a permanent blockage threshold with the reduction in the magnitude exceeding a blockage period of time, wherein the reduction in the magnitude of the calibrated signal that is greater than the permanent blockage threshold and the reduction in the magnitude exceeds the blockage period of time indicates that a blockage is present in the at least one kitchen hood system.
 12. The computer implemented method of claim 11, further comprising: ignoring the calibrated signal when the magnitude of the calibrated signal is greater than the permanent blockage threshold and the reduction in the magnitude exceeds the blockage period of time; and monitoring a temperature signal generated from at least one temperature sensor when the magnitude of the calibrated signal is greater than the permanent blockage threshold and the reduction in the magnitude exceeds the blockage period of time.
 13. The computer implemented method of claim 12, further comprising: initiating an at least one graduated action when the temperature signal fluctuates beyond a temperature threshold.
 14. The computer implemented method of claim 13, further comprising: reducing the temperature threshold associated with the temperature signal to a reduced temperature threshold when the magnitude of the calibrated signal is greater than the permanent blockage threshold and the reduction in the magnitude exceeds the blockage period of time.
 15. The computer implemented method of claim 1, wherein monitoring the calibrated signal further comprises: monitoring the magnitude of the calibrated signal for a reduction in the magnitude of the calibrated signal that is less than an auxiliary accessory threshold with the reduction in the magnitude exceeding an auxiliary accessory period of time, wherein the reduction in the magnitude of the calibrated signal is less than the auxiliary accessory threshold and the reduction in the magnitude exceeds the auxiliary accessory period of time is indicative that a gaseous substance is not present in the at least one kitchen hood system.
 16. The computer implemented method of claim 15, wherein initiating at least one graduated action further comprises: initiating a deactivation graduated action to transition at least one auxiliary accessory associated with the at least one kitchen hood system to an inactive mode when the reduction in the magnitude of the calibrated signal that is less than the auxiliary accessory threshold and the reduction in the magnitude exceeds the auxiliary accessory period of time, wherein an activation of the at least one auxiliary accessory is not required when the gaseous substance is not present in the at least one kitchen hood system.
 17. The computer implemented method of claim 16, wherein monitoring the calibrated signal further comprises: monitoring the magnitude of the calibrated signal for the reduction in the magnitude of the calibrated signal that is greater than an activating auxiliary accessory threshold, wherein the reduction in the magnitude of the calibrated signal that is greater than the activating auxiliary accessory threshold indicates that the gaseous substance is present in the at least one kitchen hood system.
 18. The computer implemented method of claim 17, wherein initiating the at least one graduated action further comprises: initiating an activation graduated action to transition the at least one auxiliary accessory associated with the at least one kitchen hood system to an active mode when the reduction in the magnitude of the calibrated signal that is greater than the activating auxiliary accessory threshold, wherein the activation of the at least one auxiliary accessory is required when the gaseous substance is present in the at least one kitchen hood system.
 19. The computer implemented method of claim 1, wherein monitoring the calibrated signal further comprises: monitoring the magnitude of the calibrated signal when at least one fan associated with the at least one kitchen hood system is in an active mode for greater than an active mode period of time; and recalibrating the magnitude of the signal when the at least one fan is in the active mode for greater than the active mode period of time.
 20. The computer implemented method of claim 19, further comprising: recalibrating the magnitude of the signal when the at least one fan is in the active mode for greater than the active mode period of time and a reduction in the magnitude of the calibrated signal that is less than a gaseous substance detection threshold, wherein the at least one fan in the active mode for greater than the active mode period of time with a reduction in the magnitude of the calibrated signal being less than the gaseous substance detection threshold is indicative that the gaseous substance is not present in the at least one kitchen hood system and that the active mode period of time has lapsed without a recalibration of the magnitude of the signal.
 21. The computer implemented method of claim 1, wherein monitoring the calibrated signal further comprises: monitoring for when at least one additional kitchen hood system previously in an inactive mode transitions into an active mode.
 22. The computer implemented method of claim 21, further comprising: recalibrating the magnitude of the calibrated signal when the at least one additional kitchen hood system previously in the inactive mode transitions into the active mode.
 23. The computer implemented method of claim 1, wherein monitoring the calibrated signal further comprises: monitoring the magnitude of the calibrated signal for an increase in the magnitude of the signal beyond an increase threshold of a current baseline of the signal, wherein the current baseline is the magnitude of the signal as adjusted during a current calibration of the signal.
 24. The computer implemented method of claim 23, further comprising: recalibrating the magnitude of the signal when the magnitude of the signal is beyond the increase threshold of the current baseline of the signal, wherein an increase in the magnitude of the signal beyond the increase threshold of the current baseline of the signal indicates that a gaseous substance is no longer located in the at least one kitchen hood system.
 25. A system for calibrating and monitoring at least one optic sensor associated with at least one kitchen hood system, comprising: a first optic sensor configured to emit a signal; a second optic sensor aligned with the first optic sensor and configured to receive the signal emitted by the first optic sensor; and a controller configured to: calibrate a magnitude of the signal by adjusting a gain associated with the signal until the magnitude of the signal is within an optimal threshold, monitor the magnitude of the calibrated signal for fluctuations in the magnitude of the calibrated signal beyond at least one specified threshold, and initiate at least one graduated action when the magnitude of the calibrated signal fluctuates beyond the at least one specified threshold, wherein the at least one graduated action reduces an overall amount of energy consumed by the at least one kitchen hood system and/or recalibrates the magnitude of the signal.
 26. The system of claim 25, wherein the controller in calibrating the magnitude of the signal is further configured to: select an initial baseline when the magnitude of the signal is initially calibrated to be within the optimal threshold so that the initial baseline is the magnitude of the signal adjusted when initially calibrated, wherein the at least one graduated action is initiated relative to the initial baseline; and automatically adjust the initial baseline to a recalibrated baseline when the magnitude of the signal is adjusted to be within the optimal threshold during a recalibration of the magnitude of the signal after an initial calibration of the signal is completed, wherein the at least one graduated action is initiated relative to the recalibrated baseline.
 27. The system of claim 26, wherein the controller is further configured to: recalibrate the magnitude of the signal to the recalibrated baseline when the magnitude of the signal fluctuates beyond the optimal threshold to account for fouling to the at least one optic sensor.
 28. The system of claim 25, wherein the controller in calibrating the magnitude of the signal is further configured to: automatically adjust the gain to a first gain setting from a plurality of gain settings when the magnitude of the signal is outside the optimal threshold; and continuing to automatically adjust the gain to a different gain setting from the plurality of gain settings until the magnitude of the signal is within the optimal threshold.
 29. The system of claim 28, wherein the controller in calibrating the magnitude of the signal is further configured to: measure a signal level associated with the magnitude of the signal, wherein the signal level is indicative of a magnitude of light included in the signal being transmitted from the first optic sensor to the second optic sensor; determine whether the signal level is within the optimal threshold, wherein the optimal threshold is a range of signal levels within a first signal level and a second signal level; automatically adjusting the gain to the first gain setting from the plurality of gain settings when the signal level is outside the range of signal levels associated with the optimal threshold; and continuing to automatically adjust the gain to the different gain setting from the plurality of gain settings until the signal level is within the range of signal levels associated with the optimal threshold.
 30. The system of claim 28, wherein the controller in calibrating the magnitude of the signal is further configured to: generate a fault signal when the gain is adjusted to each gain setting included in the plurality of gain settings and the magnitude of the signal is outside the optimal threshold.
 31. The system of claim 25, wherein the controller in monitoring the calibrated signal is further configured to: monitor the magnitude of the calibrated signal for a reduction in the magnitude of the calibrated signal that is greater than an activating threshold before at least one fan associated with the at least one kitchen hood system is in an active mode, wherein the reduction in the magnitude of the calibrated signal that is greater than the activating threshold indicates a gaseous substance is present in the at least one kitchen hood system.
 32. The system of claim 31, wherein the controller is further configured to initiate an activation graduated action to transition an at least one fan associated with the at least one kitchen hood system into the active mode when the reduction in the magnitude of the calibrated signal is greater than the activating threshold.
 33. The system of claim 32, wherein the controller is further configured to initiate a deactivation graduated action to maintain the at least one fan associated with the at least one kitchen hood system in an inactive mode when the reduction in the magnitude of the calibrated signal is less than the activating threshold indicating that the gaseous substance is not present in the at least one kitchen hood system.
 34. The system of claim 33, wherein the controller is further configured to initiate the deactivation graduated action to maintain the at least one fan associated with the at least one kitchen hood system in the inactive mode when the reduction in the magnitude of the calibrated signal is greater than a blockage threshold indicating that a blockage is present in the at least one kitchen hood system.
 35. The system of claim 25, wherein the controller in monitoring the calibrated signal is further configured to: monitor the magnitude of the calibrated signal for a reduction in the magnitude of the calibrated signal that is greater than a permanent blockage threshold with the reduction in the magnitude exceeding a blockage period of time, wherein the reduction in the magnitude of the calibrated signal that is greater than the permanent blockage threshold and the reduction in the magnitude exceeds the blockage period of time is indicative that a blockage is present in the at least one kitchen hood system.
 36. The system of claim 35, wherein the controller is further configured to: ignore the calibrated signal when the magnitude of the calibrated signal is greater than the permanent blockage threshold and the reduction in the magnitude exceeds the blockage period of time; and monitor a temperature signal generated from at least one temperature sensor when the magnitude of the calibrated signal is greater than the permanent blockage threshold and the reduction in the magnitude exceeds the blockage period of time.
 37. The system of claim 36, wherein the controller is further configured to initiate the at least one graduated action when the temperature signal fluctuates beyond a temperature threshold.
 38. The system of claim 37, wherein the controller is further configured to reduce the temperature threshold associated with the temperature signal to a reduced temperature threshold when the magnitude of the calibrated signal is greater than the permanent blockage threshold and the reduction in the magnitude exceeds the blockage period of time.
 39. The system of claim 25, wherein the controller in monitoring the calibrated signal is further configured to: monitor the magnitude of the calibrated signal for a reduction in the magnitude of the calibrated signal that is less than an auxiliary accessory threshold with the reduction in the magnitude exceeding an auxiliary accessory period of time, wherein the reduction in the magnitude of the calibrated signal that is less than the auxiliary accessory threshold and the reduction in the magnitude exceeds the auxiliary accessory period of time is indicative that a gaseous substance is not present in the at least one kitchen hood system.
 40. The system of claim 39, wherein the controller is further configured to initiate a deactivation graduated action to transition an at least one auxiliary accessory associated with the at least one kitchen hood system to an inactive mode when the reduction in the magnitude of the calibrated signal that is less than the auxiliary accessory threshold and the reduction in the magnitude exceeds the auxiliary accessory period of time, wherein an activation of the at least one auxiliary accessory is not required when the gaseous substance is not present in the at least one kitchen hood system.
 41. The system of claim 40, wherein the controller in monitoring the calibrated signal is further configured to: monitor the magnitude of the calibrated signal for the reduction in the magnitude of the calibrated signal that is greater than an activating auxiliary accessory threshold, wherein the reduction in the magnitude of the calibrated signal that is greater than the activating auxiliary accessory threshold indicates that the gaseous substance is present in the at least one kitchen hood system.
 42. The system of claim 41, wherein the controller is further configured to: initiate an activation graduated action to transition the at least one auxiliary accessory associated with the at least one kitchen hood system to an active mode when the reduction in the magnitude of the calibrated signal that is greater than the activating auxiliary accessory threshold, wherein the activation of the at least one auxiliary accessory is required when the gaseous substance is present in the at least one kitchen hood system.
 43. The system of claim 25, wherein the controller in monitoring the calibrated signal is further configured to: monitor the magnitude of the calibrated signal when at least one fan associated with the at least one kitchen hood system is in an active mode for greater than an active mode period of time; and recalibrate the magnitude of the signal when the at least one fan is in the active mode for greater than the active mode period of time.
 44. The system of claim 43, wherein the controller is further configured to: recalibrate the magnitude of the signal when the at least one fan is in the active mode for greater than the active mode period of time and a reduction in the magnitude of the calibrated signal that is less than a gaseous substance detection threshold, wherein the at least one fan is in the active mode for greater than the active mode period of time with a reduction in the magnitude of the calibrated signal being less than the gaseous substance detection threshold is indicative that the gaseous substance is not present in the at least one kitchen hood system and that the active mode period of time has lapsed without a recalibration of the magnitude of the signal.
 45. The system of claim 25, wherein the controller is further configured to monitor for when at least one additional kitchen hood system previously in an inactive mode transitions into an active mode.
 46. The system of claim 45, wherein the controller is further configured to: recalibrate the magnitude of the signal when the at least one additional kitchen hood system previously in the inactive mode transitions into the active mode.
 47. The system of claim 25, wherein the controller is further configured to: monitor the magnitude of the calibrated signal for an increase in the magnitude of the signal beyond an increase threshold of a current baseline of the signal, wherein the current baseline is the magnitude of the signal as adjusted during a current calibration of the signal.
 48. The system of claim 47, wherein the controller is further configured to: recalibrate the magnitude of the signal when the magnitude of the signal is beyond an increase threshold of the current baseline of the signal, wherein an increase in the magnitude of the signal beyond the increase threshold of the current baseline of the signal indicates that at least one optic sensor is malfunctioning. 